The objectives of this project are to determine the metabolites of aflatoxin B1 formed by the very sensitive rainbow trout. Both in vivo and in vitro systems will be used and interactions and transformations which occur in microsomal and non-microsomal systems will be investigated. The carcinogenicity and toxicity of identified metabolites will be assayed using the induction of hepatoma in the rainbow trout embryo, by animal and fish feeding trials and by assay using lethality to Bacillus subtilis GSY 1057 or use of the mutagen assay method employing Salmonella typhimurium TA 1538. The reduced metabolite of aflatoxin B1, aflatoxicol, will be fed to rats and mice to evaluate its carcinogenicity to these species. The structural requirement for toxicity and carcinogenicity will be studied and a comparison made between sensitive and resistant species of fish. BIBLIOGRAPHIC REFERENCES: Aflatoxin B1 metabolism to Aflatoxicol and Derivatives Lethal to Bacillus subtilis GSY 1057 by Rainbow Trout (Salmo gairdneri) Liver. G.L. Schoenhard, D.J. Lee, S.E. Howell, N.E. Pawlowski, L.M. Libbey and R.O. Sinnhuber. Cancer Research 36:2040-2045, 1976. Postmortem Bile Damage to Rainbow Trout (Salmo gairdneri) Livers. J.D. Hendricks, L.J. Hunter and J.H. Wales. J. Fish. Res. Board Can. 33: 2613-2626, 1976.